Is there an Open Source alternative to boxcryptor for OneNote, have there been attempts to write one?

Question

Programming

Greetings.
Spent a lot of time searching but couldn't find it.
Is there an option to keep OneNote notes encrypted?
1) As I understand it, OneNote only allows you to encrypt 1 document but not a book or the whole repo?
2) There is a boxcryptor that encrypts the entire stream (sets a proxy on the device)
What boxcryptor does not like:
- Closed software (they opened the filename encryption code)
- Limit on the number of devices - 2
I would like to find an open source alternative to it
Maybe there are some then other cloud encryption projects with OneNote support?
3) If there are no such projects, were there any attempts, articles? OneNote has an API, has anyone worked with it, does it allow you to control the flow of document synchronization?
4) An extreme case is replacing OneNote with an alternative without the above disadvantages.
- Work with notes (I would like to have a "canvas" like OneNote with the ability to insert images / audio recordings / files and handwriting)
- Encryption of all content
- Synchronization with at least one of the free cloud storage
- "Tree structure" with 2 nesting levels (in OneNote - Notebook > Section > Page)
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Thank you

Answer 1

A certain WizNote looks quite interesting, apparently it has out-of-the-box encryption and functionality close to one note, now I'm testing it